Should liver metastases of breast cancer be biopsied to improve treatment choice?

Background: Currently, the acquisition of tissue from metastatic deposits is not recommended as a routine practice. Our aim was to evaluate the discordance rate of estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) receptor status between primary tumor and liver metastases and its potential impact on treatment choice. Patients and methods: Weretrospectively analyzeda database including1250ultrasound-guided liverbiopsies carried out at the European Institute of Oncology from August 1999 to March 2009. ER, PgR, and HER2 status were determined by immunohistochemistry and/or FISH. Differences between proportions were evaluated using Fisher's exact test. Results: We identified 255 consecutive patients with matched primary and liver tissue samples. Changes in ER status were observed in 37 of 255 patients (14.5%). Changes in PgR status were observed in 124 of 255 patients (48.6%). Changes in HER2 status were observed in 24 of 172 assessable patients (13.9%). We observed a discordance in receptor status (ER, PgR, and HER2) between primary tumor and liver metastases, which led to change in therapy for 31 of 255 of patients (12.1%). Conclusions: Biopsy of metastases for reassessment of biological features should be considered in all patients, when safe and easy to carry out, since it is likely to impact treatment choice.